Apparatus for separating minerals by flotation.



B. MAcDONALD.

APPARATUS FOR SEPARATING MINERALS BY FLOTATION- APPLICATION FILED OCT. 9- 1914- 1,1. 34,690 Patented Apr. 6, 1915.

UNITED STATES, PATENT curren- BERNARD MACDONALD, or nos. Aivennns, GAIJIF RNIA.

"APPARATUS FOR SEPARATING MINERALS BY FLOTATION.

Application filed October 9, 1914. Serial No. 865,786.

To all whom it may concern Be it known that I, BERNARD MACDON- ALD, a citizen of the United States, residing in the city of Los-Angeles, county of :Los Angeles, and State of California, have invented Certain new and useful Improvements in Apparatus for Separating Minerals by Flotation; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

' ment below its surface.

This invention is directed to the provision of an improved form of apparatus for the separation of fiotable minerals from the rock or vgangue with which they occur in associ'atiOn. p l

The'practiceofthe invention involves a li minar'y crushing or grinding of the mabe treated and its mixture with wateri'a itybecbmesa freely flowing Pulp. hi ,conditiq 'tically by means of compressed air, these fpipes having their'ioutlets below the surface ofthe pulp so that the latter and the compressed air rising within the pipes are discharged into the mass undergoing treat- In this way, new supplies of the pulp are carried from the lower portion of the receptacle up into the region of the oily emulsion and are introduced therein along with substantial quantities of oil and compressed air whichvare broken up into a multiplicity ofsmall bub-' bles by contact with the pulp mass. This;- practicallycontinuous transfer of new pulp,

air and oil from the bottom of the/receptaale and the spouting of it into the upper frothy portion of the pulp charge creates theviscous emulsion of small oil-coated airbubbles' which entrap the mineralgparticles in the pulp and float them to the surface so they may be skimmed 01f.

The outlets from the Specification of Letters Patent.

transfer pip 1 9.;

Patented 'Apr. 6, 1915.

cated a short distance'below the surface of the flotation liquid are preferably "disposed circumferentially so that the pulp within the receptacle is caused to take up a circular motion within the receptacle. This permits of readily skimming oif the froth upon the surface of the flotation liquid the provision of a guide or. diverting board which directs the froth over a skimming board. and

intoa suitable launder. Also, the outlets from the transfer-pipes are preferably @1011:

gated horizontally so that the-air and material issuing therefrom take the form of a 3 wide thin sheet. This assists in breaking up, the air into a multiplicityof small bubbles and in mixing the air and sulfi'd particleswith the oily material in the upper portion of the receptacle. n I

Another feature of the invention resides in the provision of a receptacle for the pulp of annular form and means for causing the liquid to flow in a circular direction around this receptacle. Preferably, a cylindrical tank is employed as the receptacle fol-the pulp and a circular diaphragm is mounted within the upper portion Of' 'this receptacle and'concentric therewith. llhisforms between the diaphragm and the wall of thereceptaclean annular space around-which the frothy emulsion may be caused to flow until it comes to the skimmer over which the froth is carried off to the launderl Preferably, the circular diaphragm is opiejn at its lower end so that the pulp rises within it, but it is of sufficient de th to retainthe oily emulsion in the annu ar space between it andthe wall of the receptacle.

7 Another feature of the invention res ides in the provisionof means for introducing oil and suchother material as may be found desirable aloiig with the compressed air into the lower ends of the transfer-pipes so that' the oil and pulp are pumped upwardly by the air and the oil, pulp and compressed air are discharged together into the upper portimately mixed with each other. In this Way, the pulp is brought into more intimate mixture with the oily froth which entraps i and carries to the surface the valuable min-' gaiigue or rocky material the receptacle.

of tlicpulp, which the oily froth has no afiinity, bee separated from the valu-' able mine sinks through the pulp tion of the receptacle, thereby becoming in- I have illustrated the preferred embodiment ofmy invention in the accon'ipanyil'ig drawings, in which?- Figure 1, is a top v1ew of the apparatus;-

ends and forming between it and the surrounding wall of the tank 4 an annular space within which. the "oily emulsion is adapted to move circumferentially. Within the receptacle are a plurality of transfer pipes 6 mounted vertically within their lower intake ends a short distance above the bottom of the receptacle 4. These pipes 6 receive the pulp in the tank at their lower ends and this pulp is forced upwardly through the pipes by compressed air. This air is admitted to the lower ends of the pipes 6 throughcompressed air pipes 7 extending upwardly through the bottom of the tank and having their upper ends projecting within the lower, open ends of the transferpipes 6. At the'upper ends of the transfer-i pipes 6 are discharge outlets 8 which are I directed Icircumferentially; Each of the outlet-members 8 has an orifice which-isin the form of a horizontally elongated slot so I that the material issuing from the upper end of the transfer-pipe is in the form of a wide thin she etl :By reason of the circumferential arrangement of the outlets at the upper ends of the pipes 6, the material within the receptacle 4'and particularly theportion of the material within the annular chamber between'the diaphragm 5.and the wall of the receptacle 4 is caused to take up a circular movement within thetank. As the material moves thus, a froth is formed,

thereon by the agitation of the material discharged from the pipes and the admixture of oiland air therewith, and this froth rises to the surface of the pulp and is carried around the tank in the annular space out side 'thediaphragm 5. At one or more points around the upper edge of the wall of receptacle 4, that. wall is cut away. as

shown in Fig. so as to form a skimmer- I air; A receptacle 14 for the oil employed .in V producing the emulsion is also connected to over which the frothy material at-the sur face of the pulp maypass into a launder 1O by which it is carried to the apparatus for effecting the further treatment of the minerals carried by the froth. To assist in effecting the passage of the froth over the skimmer, a deflector or diverting board 11 is placed in position upon the diaphragm 5 and the wall of the receptacle at an incline to the direction of the travel of the material as shown in .Figs. 1 and 3 so that this deflector 11 causes the froth to pass from the receptacle into the launder 10. In order to provide for adjustment of the height'ofthe skimmer, a board separate from the wall of the receptacle is preferably employed. This 'board is shown at 21 in Fig. 3. It is laid against the. inner side of the wall of the receptacle as-shown and is sustained in position by bolts 22 depending from a bar 20 secured to the upper edge of thereceptacle.

. By turning the nuts 19 on the bolts 23, the height of the board 21' may be regulated as desired. I Y I It will be noted by reference to Fig. 2 that the discharge outlets of the transferpipes. (i-are located belowthe level of the flotation liquid in the receptacle 4, this level being/established by the position of the skimmer 21 over which the'oily froth with the entrapped minerals flows into the'launder 10. Because of this, the air, oil and pulp to be treated issue fromthe transferpipes into the body of the pulp within the receptacle." The resistance whichthe mass of the pulp in the receptacle offers to the portion spouted from the transfer-pipes iaids materially in the formation of the viscous emulsion of small oil-coated air-bubbles which is desirable for the flotation of the-mineral particles.

has a conical shape as shown at 12- This cone upon the bottom of the receptacle. serves- .to-.-divert thicker portionsof the pulp ;within the receptacle toward the intake ends pf the transfer-pipes so that they may be The bottom of he receptacle 4 preferably carried upwardly through the pipes and again subjected to the flotation effect of the emulsion in the upper portion ofthe' receptacle. v l The introduction of compressed air into the lower ends of the pipes 6 through the air supply pipes 7. causes the pulp to be raised within the pipes 6 in a plurality of layers separated by'disks or pistons of compressed air as disclosed in my Patent- No.

1,071,447 granted August 26, 1913.: I. have found it highly desirable to. provide for the admission of the oil and other. materials requiredfQr theflotation emulsion throu gh Y the pips-Tfwfhich carry the compressed air to theitransfer-pipes 6. In Fig. 2, the pipes '7 are shown as connected to a pipe 13 leading froni a source of supply'of compressed transfer-pipes 6 to the flotation liquid with- 'in' the receptacle 4. Any suitable means,

such as a pump, maybe provided for effectin'gthe flow of the oil from the receptacle 14. In Fig: 2, I .have shown a pipe 17 connecting the upper portion of receptacle 14: with the air supply pipe -13 so that the oil within the receptacle 14 may be subjected tov pressure.

, In the pipe 17 is a valve 18 whereby the flow may be regulated as desired so as to cause the introduction of the desired amount of oil into the pulp. By this provision for the introduction of the oil and other materials required for the flotation emulsion, these materials maybe readily introduced in such fecting the radial movement ofthe-froth quantities as'may be found desirable for the production of the emulsion best suited for the material being treated. Also, the ad-;

mission of the oil along with the air facilitates the production of the emulsion by-the formation of a multiplicity ofsmall oil'- coated air-bubbles from the compressed-air issuing from the outlets of the transferpipes.

The material within the diaphragm 5does not partake of the circular motion given to the'material outside the diaphragm to any substantial extent. Therefore, the solid con-l stituents of the material within the dia-.

phragm settle to the bottom leaving clear water within the diaphragm. This waterv being of lower specific gravity than the pulp, rises to alevel slightly higher than the. level. of the pulp in the annularjspace be-'.

tween the diaphragm 5 and wall 4. I utilize' this water at the higher level toassisti in carrying the froth over the skimmer 21.

For this purpose, a plurality of holes-9 are provided in the wall of the diaphragm 5' opposite the sln'mmer 2-1 through which small streams of water pass radially-from within the diaphragm and these streamsald 1n efand over the skimmer. For the introduction of. the pulp outletv is a substantial distance below the surface of the materialin the receptacle.

Such a conduit is shown at 23. A pipe-24 -may be connected to this-conduit? tozconvey acid thereto. With the apparatus thus';con-

structed, the pulp'material is delivered *i-nto.. the tank at a considerable distance below the surface; it then settles to the lower portion of the tank where it is taken up by the transf fer-pipes, pumped to the surface of the pulp' material and mixed with the oil and air.

In the operation of the apparatus, the tank or receptacle 4 is filled with the material to be treated'so that the surface ofthe material is close to the edge of the skimmer separating the launder 10 from the interior of the receptacle. Compressed air is then admitted through the pipes 13 and 7 to the lower ends of the transfer-pipes 6 and serves to dra'tv the pulp at the bottom of the tank 4 into the lower ends of the transfer-pipes and carry into-the a receptacle 4, a conduit is provided whose it upwardly to the upper portion of the'tank where it is'discharged circumferentially into the annular space betweehthe -cylindrical diaphragm 5 andthexwalln-fof the receptacle 4. The material discharged through the out lets of the transfer-pipes is given the form of a thin sheet so that the air is broken up into a multiplicity of small bubbles. The

discharge of air along with the pulp into the material'within the. receptacle 4 below the surface of that-material assists in the formation of the desirable emulsion and the intimate admixture of the pulp therewith and a froth appears upon the-surface of the material in which the'mineral particles are floated. This froth partakesof the circular motion of the pulp caused by the circumferential discharge from the transfer-pipes 6 and passes around in the annular space between the diaphragm 5 and the wall'of the receptacle until it comes. into contact with the deflector 11 by which the froth iscaused I to pass' over the skimmer and into the launder 10. I" v a I "WhatIclaim is: 1 v1'. Apparatus for separating metal 1minerals by flotation from associated gangue or rock comprising the combination of a receptacle, a transfer-pipe therein having a -lower open intake. end terminating within the lower. portion of the receptacle and an upper discharge end, means for effecting the flow of the material in the receptacle upwardly through the'transfer-pipe, a launder and awallrover which the surface material in 'the receptacle passes from'the receptacle to.the launder, theoutlet from said pipe bev locatedbelowthe surface of the materialin the receptacle andsdirected laterally so .that '-thematerial "issuing therefrom will cause'movement of the material in the re- -ceptacl in=a direction to carry the froth upon the material to said wall, substantially as described. I p

2. Apparatus for separating metal minerals by flotation from associated gangue or rock comprising the combination of a receptacle, a plurality of vertically disposedtransfer-pipes therein having lower open intake ends and upperdischarge ends directed horizontally. and substantially parallel to J the wall of'the receptacle, means for admit-' tingcompressed air to the lower ends of the transfer-pipes to effect the flqw of the material iii the receptacle upwardly through. the;

transfer pipes, a launder and a wall'over rock' comprising the combination of a re-- ceptacle, a vertically disposed transfer-pipe therein having a lower open intake end terminating within the lower portion of the receptacle and an upper discharge end having an elongated discharge outlet which is directed laterally, means for effecting the flow of the material in the receptacle .up

wardly through thetransfer-pipe, a launder and a wall over which the surface material in the receptacle passes from the receptacle to the launder, which wall is located above the discharge outlet of the transfer-pipe, substantially as described.

4. Apparatus for separating minerals by flotation comprising the combination of a cylindrical receptacle, a cylindrical diaphragm within the upper end of the receptacle, a transfer-pipe disposed vertically within the receptacle and having its upper discharge end located between said diaphragm and the wall of the receptacle, means-for effecting the flow of the material in the receptacle upwardly through the allel' to the wall of the receptacle, means forefiecting the flow of the material in the receptacle upwardly through the. transfer p pes, a launder and a wall over which the material passes from the receptacle into the launder, substantially as described.-

6. Apparatus for separating mineralsby flotation comprising the .combination of a cylindrical receptacle, .a cylindrical diaphragm located concentrically within the upper end of the receptacle,- a plurality of vertically disposed transfer-pipes in the receptacle having open lower intake ends and upper discharge ends located between the diaphragm and the wall of the receptacle and provided with elongated discharge outlets directed substantially parallel to the wall of the receptacle, means for eifecting the flow of the material in the receptacle upwardly through the transfer-pipes, a launder, and a wall over which the material passes from the receptacle into the launder which wall is located, above the discharge outlets of the transfer-pipes whereby said pipes are caused to discharge below the surface of the material in the receptacle substantially as described.

7. Apparatus for separating minerals by flotation comprising the combination of a cylindrical receptacle, a cyl1ndr1cald1aphragm located concentrically withinv the upper end of the receptacle, means for delivering the pulp in a circumferential direction into the annular space between said diaphragm and the wall 01" the receptacle to cause the material within said space to take a circular motion within the receptacle, a;

launder, a skimmer. upon the wall of the receptacle over which the froth on the material inthe receptacle passes from the receptacle into the launder and a deflector extending from the diaphragm to the wall of the receptacle adjacent-to said skimmer for deflectingthe froth over the skimmer, substantially as described.

8. Apparatus for separating minerals by flotation comprising the combination of acylindrical receptacle, a cylindrical diaphragm located concentrically within the upper end of the receptacle, a plurality of vertically disposed transfer-pipes within the receptacle' having open lower intake ends and upper discharge ends located between the diaphragm and the wall of the receptacle, and directed substantially parallel to ,the wall of the receptacle, a launder into .which the materialpasses from the receptacle and a deflector extending from the diaphragm to the wall of the receptacle for deflecting the material in the receptacle into the launder, substantially as described.

7 9. Apparatus for-separating minerals by flotation comprising a receptacle, a launder adjacent to the receptacle into which the material passes from the receptacle, a vertically disposed transfer-pipe within the receptacle having a lower open intake end and an upper discharge end, a pipe entering the lower open end of the transfer-pipe, means for supplying compressed air to said last mentioned pipe and means for supplying oil to said last'mentionedpipe, substantially as described. I I

10. Apparatus'for separating minerals by flotation comprisingthe combination of a receptacle, a launder adjacent thereto, into which the material passes from the receptacle, a plurality of vertically disposed transferrpipes in the receptacle having discharge outlets at, their upper ends located below the level of the material in the receptacle and directed horizontally and substantially parallel to the wallof the recepj tacle and means for supplying oil and'cmnpressed air to the lower open ends of the transfer-pipes, substantially as described.

11. Apparatus for separating minerals by flotation comprising the combination of a receptacle, a cylindrical diaphragm located concentrically within the upper end of the receptacle, a launder adjacent to the recepthe receptacle, a plurality of Vertically disthe launder, a divertor extending rom the erals by flotation from associated gangue or rock comprising the combination of a.re-' ceptacle, a plurality of vertically'disposed posed transfer-pipes 'inthe receptacle having open lower intake ends and upper dis- 7 charge ends located between said diaphragm and the wall of the receptacle andprovided with outletswhich are directed horizontally and substantially parallel to the wall of the receptacle, said outlets being located below the level of thematerial inthe receptacle,

and means for supplying oil and compressed. air to the lower open ends of the transfer-' pipes, substantially as described.

12. Apparatus for separating minerals by flotation comprising the combination .of a receptacle, a cylindrical diaphragm located concentrically within the upper end of the receptacle and open at its lower end, a launder, a skimmer over which the material in the receptacle passes from the rece tacle to diaphragm to the wall of the receptacle adjacent to the skimmer, and means for causing circular flow of the material between the diaphragm and the wall of the receptacle, said. diaphragm having a plurality of openingstherethrough near its upper ,edge and opposite the skimmer, substantially as described.

13. Apparatus for separating metal mintransfer-pipes therein having lower open intake endsand upper discharge ends directed horizontally-and substantially parallel to the wall of the receptacle, means for effect-- ing the flow of the material in the receptacle upwardly through the transfer-pipes,- a launder into which the frothon the material in the receptacle passes, and means for conveying the pulp material to the receptacle and delivering it into the receptacle at a substantial distance below the level of said skimmer, substantially described.

14. Apparatus for separating metal minerals by flotation from associated gangue or rock comprising the combination of a receptacle in which the pulp is agitated and a froth accumulates on the surface of the pulp, a transfer-pipe in the receptaclehaving a lower open intake endterminating within the receptacle at a substantial distance below the top thereof and-an upper discharge ment of the material in the receptacle in a direction to carry the froth upon the mateas described... I

15. Apparatus for separating metal minerals by flotation from associated gangue or rock comprising the combination of a-receptacle in which the pulp is agitated and in which a frothaccumulates on the surface of the pulp, a vertically disposed transfer-pipe in the receptacle having an upper discharge end directed substantially horizontally and a lower'open intake end terminating within the receptacle'at av substantial, distance below the top thereof, devices for admitting air under pressure to the lower end of the transfer-pipeto effect a flow of the pulp upwardly through thetransfer-pipe and means for determining the level of the pulp in the receptacle,said transferipe-being of such height that its upper en is below'the level of the pulp in the receptacle as determined by said means, substantially as described.

16. Apparatus for separating metal minerals by flotation front associated gangue or rock comprising the combination of a receptacle in which the pulp is agitated and in which a froth accumulates on the surface of the pulp, a plurality ofvertically 'dis posed transfer'pipes in the freceptacle having upper discharge ends directed substantially horizontally and provided with elonlevel of the material in the receptacle, said transfer-pipes being of such height that their discharge outlets are below the level ofthe material in the'receptacle as deter.-

mined by said means, and said outlets-being directed laterally so that the material issuing therefrom will cause movement'of the material in the receptacle in a direction to erals-by flotation from associated gangue or rock comprising the combination of a receptacle in which the pulp is agitated anda froth accumulates. on "the surface of the pulp, a transfer-pipe in the receptacle hav-'' ing a lower-fopen intake end terminating within thefreceptacleat a" substantial distance below the top thereof'a nd an upper dischargeend; means fortelfecting the flow of the material the'receptacle upwardly through the transfer-pipe, and collecting devices for collecting the froth accumulating on the surface of the pulp in the receptacle,

the discharge outlet from said transfer-pipe being directed laterally so-that the material issuing therefrom will cause movement of the material in-the receptacle to carry the froth thereon to said collecting devices, substantially 'as described.

18; Apparatus'for'separating metal minerals by flotation from associated gangue or rock comprising the combination of a receptacle in which the pulp is agitated and a froth accumulates upon' the surface of the pulp, a verticallydisposed transfer-pipe in the-receptacle having a lower open intake end terminating within the receptacle at a substantial distance below the top thereof and an upper discharge end, means for admitting compressed air to the lower portion of the transfer-pipe to cause the material in the receptacle to flow upwardly through the transfer-pipe, and collecting devices for collecting the froth accumulating upon the surface of thematerial in the receptacle, the discharge outlet from said transfer-pipe being directed laterally so that the material in presence of two' witnesses. BERNARD MACDONALD. Witnesses:

DONALD FERGUSON; En. MAAG.. 

